They pop up on all websites. On some sites, all I have to do is get the cursor anywhere near a small advertisement, and it pops up to life-size.

I have a free pop-up stopper from Panicware that used to be good, but now it doesn’t stop most ads, especially the ones with video and sound.

Is there any way to stop these annoying ads before I throw the computer out the window? — Tracy Anton, Miami

A: I doubt that your pop-up blocker software is failing. More likely your computer has been infected by malicious software that is prompting these advertisements to appear.

Download the free Malwarebytes Anti-Malware program at http://tinyurl.com/blqaum7. Click “Download Now” and you’ll be taken to a download page; ignore the Web page and find, at the bottom of your screen, a rectangular download box that says, in part, “Do you want to run or save mbam-setup-1.75.0.1300 .exe?” Click on “run.” When the installation is complete, uncheck the box next to “Enable free trial,” click “Finish,” let the program update, then click “OK.” When Malwarebytes starts, use its default setting “run quick scan” and click “Scan.” You’ll be given a list of questionable programs on your PC; choose to delete them. Periodically run this program from its desktop icon to keep your PC clean.

Now take some preventive action by either turning on the pop-up blocker that is built in to Internet Explorer 10 or downloading a new pop-up blocker program. Because you gain nothing by having two pop-up blockers simultaneously, I suggest you uninstall your original Panicware program. To do this, click “Start,” choose “Control Panel,” click “Programs and Features” and follow the directions.

To turn on Internet Explorer 10’s own pop-up blocker, click on the “Tools” heading, and choose “Internet Options.” Then click on the “Privacy” tab and check the box in front of “Turn on Pop-up Blocker.” To download another free pop-up blocker, see http://tinyurl.com/lteapve.

Q: Ever since I installed Windows 7 Pro, the “Devices and Printers” function in Control Panel doesn’t work because it never finishes loading. That means I can’t control any printer linked to my PC. What should I do? — Robert Simpson, Faribault, Minn.

A: Microsoft suggests possible solutions at http://tinyurl.com/nb22cuw. They include restarting your computer with only the minimum number of programs running (to eliminate potential software conflicts) and updating the printer software drivers for each of the printers you use. You should skip suggestion 5, to run an online virus scan, and instead run Malwarebytes software described above.